生态系统内形成的生态平衡，其平衡的性质是（） A.自然的、暂时的相对平衡 B.封

某同学设计了利用废旧电池中的锌皮制取干燥、纯净的氢气，并验证该气体中杂质的实验。请回答下列问题：

(1)若实验中看到____________________现象，可证明产生的气体中含有水蒸气，除此之外还可能含有的气体杂质的化学式是__________；

(2)如果用E装置检验该杂质，则E中所放试剂的名称为__________，E应连接在上述装置中_______（填字母）之间。

(3)装置C的作用是_____________________，D中所放试剂的名称为____________。

    “仙女木”是寒冷气候的标志植物，因此用来命名出现在北欧的寒冷事件，“新仙女木”表示末次冰期的最后一次寒冷事件。“新仙女木”事件之后气候变暖，进入温暖的全新时期。图甲是地球50万年前至今的气温变化模拟曲线图，图乙是地球2万年前至今的海平面模拟变化图，回1—2题。

1、图乙中①、②、③、④表示“新仙女木”事件的是[ ]

A、①

B、②

C、③

D、④

2、下列叙述错误的是[ ]

A、气温变化与海平面变化的趋势是一致的

B、近7千年来气温相对保持平稳

C、近2万年来气温与海平面始终保持上升

D、50万年前至今气候呈冷暖交替变化

I first went to hear a live rock concert when I was eight years old. My brother and his friends were all fans of a heavy metal group called Black Wednesday. When they discovered that Black Wednesday were going to perform at our local theatre, they all bought (21) for the performance. However, at the last minute, once of the friends couldn’t go, so my brother offered me the ticket. I was really excited!

I remember the buzz (嘈杂声) of excitement inside the theatre as we all found our seats. After a few minutes, the lights went down and everybody became quiet. I could barely make out the stage in the (22) . We waited. Then there was a roar from the crowd, like an explosion, as the first members of the band stepped onto the stage. My brother leaned over and shouted something in my ear, but I couldn’t hear what he was saying. The first song was already starting and the music was as (23) as a jet engine. I could (24) the drum beats and bass notes in my stomach.

I can’t recall any of the songs that the band played. I just (25) that I really enjoyed the show and didn’t want it to (26) . But in the end, after three encores (加演), the show finished. We left the (27) and walked unsteadily out onto the pavement. I felt a little dizzy, as if I had just woken from a long sleep. My ears were still (28) with the beat of the last song.

After the (29) , I became a Black Wednesday fan too for a few years before getting into other kinds of music. Once in a while, though, I listen to one of their songs and (30) I’m back at that first show.

22（）

A.silence 

B.noise 

C.darkness 

D.smoke

进气终了阻力（），进气终了压力增高，则充气系数提高。

A、降低

B、增高

C、不变

D、不能确定

办事公道的具体要求不包括（）。

A、坚持真理

B、公私分明

C、不计得失

D、公平公正